When a fallback is shown there is a helpful icon that shows WHY it was blocked, be it performance, file size, platform incompatibility, etc (https://docs.vrchat.com/docs/avatar-fallback-system). However, when an imposter is shown the icon simply tells you that it's an imposter and not WHY you're being shown the imposter.

I use relatively strict performance blocking settings, and I use the fallback system icon when I'm deciding whether or not to manually show an avatar, so the icon lacking detail for imposters is impactful to my experience. With normal fallbacks I get a small hint if showing the avatar would be a bad idea. With imposters I frequently find myself having to press "show" to see how bad the avatar is and getting punished with a 500MB download.

I'm not sure if this is intentional design or an oversight, but either way I'd like the fallback system icons to work on imposters.